The present invention relates to environmental control systems. More specifically, the present invention relates to an environmental control system including a vapor cycle system and an air filtration system for removing chemical and biological agents, toxic industrial chemicals (TICs) and toxic industrial materials (TIMs).
An air cycle system may be used to condition incoming air to a desired temperature, pressure, and humidity before the air is supplied to an enclosed environmental space. Aircraft cabins and gas turbine-powered tanks are typical of the enclosed environmental spaces that allow air cycle systems to be used.
In certain applications, it is highly desirable to remove nuclear, chemical and biological (NBC) agents from the air before the air reaches the enclosed environmental space. Protection against NBC agents may be provided via packed beds of impregnated activated carbon and high efficiency particulate air (HEPA) filters.
For closed environmental spaces where the air is not pressurized, vapor cycle systems (VCS) are often used to condition the air. Such environmental spaces may include helicopters, buildings, tents, diesel and gasoline-powered tanks, and shelters.
However, removing NBC agents can be a problem. Packed beds of carbon may be employed, but they are less efficient in unpressurized air streams because of their pressure drop and because adsorption is more difficult at lower pressures.